Vacuum-Assisted Stereotactic Breast Biopsy

Abstract

IMAGE-GUIDED CORE biopsy is becoming the standard of care in the diagnosis of nonpalpable breast abnormalities. Both ultrasound-guided and stereotactic core biopsy have been shown to rival the accuracy of open (surgical) wire localization biopsy, while minimizing patient morbidity and cost.^1-4 Although these minimally invasive techniques possess significant advantages compared with open biopsy, certain drawbacks exist. Because stereotactic core biopsy yields fragmented samples of the mammographic abnormality, the entire breast lesion is often not available for histologic interpretation; thus the tissue diagnosis may change (underdiagnosis) following subsequent excision and evaluation of the remaining lesion. Underdiagnosis occurs when core biopsy specimens are diagnosed as atypical ductal hyperplasia (ADH) but contain carcinoma on follow-up excision, or when core biopsy specimens show ductal carcinoma in situ (DCIS) but invasive cancer is present on reexcision. These inaccuracies may lead to the need for additional surgical procedures, with associated increased patient morbidity, cost, and anxiety. This is particularly an issue when invasive carcinoma is initially understaged as DCIS and a subsequent additional axillary lymph node staging procedure is required after a lumpectomy is performed. Another potential drawback of image-guided biopsy occurs when harvesting multiple large cores of tissue results in the removal of the entire tumor, rendering it difficult to accurately determine the exact pathologic tumor size. This information is important in determining the benefit of adjuvant chemotherapy in axillary node–negative patients and has been shown to be the most accurate predictor of lymph node status and recurrence.⁵ Fortunately, the majority of mammographic abnormalities are benign; this is where the benefits of image-guided core biopsy are best observed. Nevertheless, understaging and accurate measurement of tumor size remain problematic in the patients with atypical hyperplasia, DCIS, and small invasive tumors.